Ziller Forum

second stage regulator for 22kw using propane. Generac Air Cooled Generators
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Member 46 posts jallis Member 46 posts
jallis
I have a Rego LV4403B66R second stage propane regulator on my current 15kw and have just bought a new Generac 22kw. Is this model regulator suitable for the new generator?
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Geoff Z Administrator 3,778 posts
Geoff Z
Yes it is suitable. Once 22kw is installed, I would test WC pressure static and in operation under full load. Never assume it is set correctly. Proper fuel delivery is critical.
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jallis Member 46 posts
jallis
Thanks.
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78buckshot Administrator 8,719 posts
78buckshot
LP industry standard is to replace the regulators if they are 10 years old or more.
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Geoff Z Administrator 3,778 posts
Geoff Z
Hmmm...never heard that before. What can happen? Spring loose it's tension? Diaphragm become brittle?
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78buckshot Administrator 8,719 posts
78buckshot
LP is a little different than natural gas. As the liquid in the tank changes to lower pressures at each regulator, the temperature of the gas will drop, this can and often will result in frost or condensation forming on the cold metal components. The outdoor LP regulators are exposed to varying temperatures, humidity, environmental contaminants, and the corrosive additives in the LP gas itself. The changing temperatures and resulting oxidation will corrode the springs and eventually the interior of the regulator housing. With enough age, the diaphragm will also deteriorate. I also have had to argue with natural gas suppliers to get them to replace natural gas regulators, they don't like outside technicians condemning their equipment but when I find a regulator than leaks or won't lock-up at the set pressure I call them on it.
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Geoff Z Administrator 3,778 posts
Geoff Z
Thanks for the explanation. Freezing makes sense. Especially when the ambient temperature is below freezing. That has to be hard on the regulator components over time. 

Ok, can't help myself...segue: Few years back I had some steaks on the grill. Tank was getting low. Froze my regulator and grill shutdown. For burgers I would have employed the skillet on the stove...for steaks I got a hair dryer and kept the regulator thawed out...I'm sure I looked like an idiot!!
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78buckshot Administrator 8,719 posts
78buckshot
Yup, I bet you have seen frost on the LP tank on your fork lift in the middle of summer. When the tank gets low on liquid or the fuel use is high, the vaporization rate is great enough to drop the lp pressure at the restriction point below freezing. Propane was used as a refrigerant, maybe in some cases still is, I think some refrigerant blends still have propane in them.
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Geoff Z Administrator 3,778 posts
Geoff Z
Two fork lifts and neither have ever froze. Tank goes empty and they stall. I'm surprised at no freezing now that you mention it? There is no visible regulator? On a fork lift does LP stay liquid until it reaches a vaporizer or something?
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Birken Vogt Senior Member 1,910 posts
Birken Vogt
The fork lift draws liquid from the bottom of the tank and uses hot water from the engine to vaporize it.  Liquid draw does not chill the tank much. 
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Littletommy Senior Member 111 posts
Littletommy
78buckshot wrote:
Yup, I bet you have seen frost on the LP tank on your fork lift in the middle of summer. When the tank gets low on liquid or the fuel use is high, the vaporization rate is great enough to drop the lp pressure at the restriction point below freezing. Propane was used as a refrigerant, maybe in some cases still is, I think some refrigerant blends still have propane in them.


You reminded me of when I lived on the southern border many years ago. As you drove across the International bridge coming out of Mexico, the kids would go car to car selling small cans of 'freon'. It was actually propane!
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New16Kw Senior Member 294 posts
New16Kw
The second stage regulators on this house were moved and reused in 98 or 99 when I made some changes.  A couple of years back when I installed the GenSet, I had to completely remove one while I reworked the gas lines.  Put it back in, charged the line and weird stuff happened.  The LP stove burners would light, but the oven would not.  Radiant LP wall heaters would work fine, but the forced air furnace burner would not ignite.  It would go through the motions, I could hear the gas valve open (solenoid click), but then it would time out and shut down.

I had no idea what was happening, but figured the regulator had failed or gotten fouled somehow.  I needed a new 3/4" for the GenSet anyways, so I ordered that and a new 1/2" unit.  Installed it and all was well again.

I have no idea how old it was, only that it was here in '98 when i bought the house and for quite some number of years before that.
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